package com.alipay.api.internal.util.json;

import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Array;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.text.CharacterIterator;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.text.StringCharacterIterator;
import java.util.Collection;
import java.util.Date;
import java.util.Iterator;
import java.util.Map;
import java.util.Stack;
import java.util.TimeZone;

import com.alipay.api.AlipayConstants;
import com.alipay.api.internal.mapping.ApiField;
import com.alipay.api.internal.mapping.ApiListField;
import com.alipay.api.internal.util.AlipayLogger;

public class JSONWriter {

    private StringBuffer buf = new StringBuffer();

    private Stack<Object> calls = new Stack<>();

    private boolean emitClassName = true;

    private DateFormat format;

    public JSONWriter(boolean emitClassName) {
        this.emitClassName = emitClassName;
    }

    public JSONWriter() {
        this(false);
    }

    public JSONWriter(DateFormat format) {
        this(false);
        this.format = format;
    }

    public String write(
            Object object) {
        return write(object, false);
    }

    public String write(
            Object object,
            boolean isApiModel) {
        buf.setLength(0);
        value(object, isApiModel);
        return buf.toString();
    }

    public String write(
            long n) {
        return String.valueOf(n);
    }

    public String write(
            double d) {
        return String.valueOf(d);
    }

    public String write(
            char c) {
        return "\"" + c + "\"";
    }

    public String write(
            boolean b) {
        return String.valueOf(b);
    }

    private void value(
            Object object) {
        value(object, false);
    }

    private void value(
            Object object,
            boolean isApiModel) {
        if (object == null || cyclic(object)) {
            add(null);
        } else {
            calls.push(object);
            if (object instanceof Class<?>) {
                string(object);
            } else if (object instanceof Boolean) {
                bool(((Boolean) object).booleanValue());
            } else if (object instanceof Number) {
                add(object);
            } else if (object instanceof String) {
                string(object);
            } else if (object instanceof Character) {
                string(object);
            } else if (object instanceof Map<?, ?>) {
                map((Map<?, ?>) object);
            } else if (object.getClass().isArray()) {
                array(object, isApiModel);
            } else if (object instanceof Iterator<?>) {
                array((Iterator<?>) object, isApiModel);
            } else if (object instanceof Collection<?>) {
                array(((Collection<?>) object).iterator(), isApiModel);
            } else if (object instanceof Date) {
                date((Date) object);
            } else {
                if (isApiModel) {
                    model(object);
                } else {
                    bean(object);
                }
            }
            calls.pop();
        }
    }

    private boolean cyclic(
            Object object) {
        Iterator<Object> it = calls.iterator();
        while (it.hasNext()) {
            Object called = it.next();
            if (object == called) {
                return true;
            }
        }
        return false;
    }

    private void bean(
            Object object) {
        add("{");
        BeanInfo info;
        boolean addedSomething = false;
        try {
            info = Introspector.getBeanInfo(object.getClass());
            PropertyDescriptor[] props = info.getPropertyDescriptors();
            for (PropertyDescriptor prop : props) {
                String name = prop.getName();
                Method accessor = prop.getReadMethod();
                if ((emitClassName || !"class".equals(name)) && accessor != null) {
                    if (!accessor.isAccessible()) {
                        accessor.setAccessible(true);
                    }
                    Object value = accessor.invoke(object, (Object[]) null);
                    if (value == null) {
                        continue;
                    }
                    if (addedSomething) {
                        add(',');
                    }
                    add(name, value);
                    addedSomething = true;
                }
            }
            Field[] ff = object.getClass().getFields();
            for (Field field : ff) {
                Object value = field.get(object);
                if (value == null) {
                    continue;
                }
                if (addedSomething) {
                    add(',');
                }
                add(field.getName(), value);
                addedSomething = true;
            }
        } catch (IllegalAccessException iae) {
            iae.printStackTrace();
        } catch (InvocationTargetException ite) {
            ite.getCause().printStackTrace();
            ite.printStackTrace();
        } catch (IntrospectionException ie) {
            ie.printStackTrace();
        }
        add("}");
    }

    private void model(
            Object object) {
        add("{");
        boolean addedSomething = false;
        Field[] ff = object.getClass().getDeclaredFields();
        try {
            for (Field field : ff) {
                // 获取注解
                ApiField jsonField = field.getAnnotation(ApiField.class);
                ApiListField listField = field.getAnnotation(ApiListField.class);
                // 优先处理列表类型注解,非列表类型才处理字段注解
                if (listField != null) {
                    PropertyDescriptor pd = new PropertyDescriptor(field.getName(), object.getClass());
                    Method accessor = pd.getReadMethod();
                    if (!accessor.isAccessible()) {
                        accessor.setAccessible(true);
                    }
                    Object value = accessor.invoke(object, (Object[]) null);
                    if (value == null) {
                        continue;
                    }
                    if (addedSomething) {
                        add(',');
                    }
                    add(listField.value(), value, true);
                    addedSomething = true;
                } else if (jsonField != null) {
                    PropertyDescriptor pd = new PropertyDescriptor(field.getName(), object.getClass());
                    Method accessor = pd.getReadMethod();
                    if (!accessor.isAccessible()) {
                        accessor.setAccessible(true);
                    }
                    Object value = accessor.invoke(object, (Object[]) null);
                    if (value == null) {
                        continue;
                    }
                    if (addedSomething) {
                        add(',');
                    }
                    add(jsonField.value(), value, true);
                    addedSomething = true;
                }
            }
        } catch (IntrospectionException e1) {
            AlipayLogger.logBizError(e1);
        } catch (IllegalAccessException e2) {
            AlipayLogger.logBizError(e2);
        } catch (IllegalArgumentException e3) {
            AlipayLogger.logBizError(e3);
        } catch (InvocationTargetException e4) {
            AlipayLogger.logBizError(e4);
        }
        add("}");
    }

    private void add(
            String name,
            Object value) {
        add(name, value, false);
    }

    private void add(
            String name,
            Object value,
            boolean isApiModel) {
        add('"');
        add(name);
        add("\":");
        value(value, isApiModel);
    }

    private void map(
            Map<?, ?> map) {
        add("{");
        Iterator<?> it = map.entrySet().iterator();
        while (it.hasNext()) {
            Map.Entry<?, ?> e = (Map.Entry<?, ?>) it.next();
            value(e.getKey());
            add(":");
            value(e.getValue());
            if (it.hasNext()) {
                add(',');
            }
        }
        add("}");
    }

    private void array(
            Iterator<?> it,
            boolean isApiModel) {
        add("[");
        while (it.hasNext()) {
            value(it.next(), isApiModel);
            if (it.hasNext()) {
                add(",");
            }
        }
        add("]");
    }

    private void array(
            Object object,
            boolean isApiModel) {
        add("[");
        int length = Array.getLength(object);
        for (int i = 0; i < length; ++i) {
            value(Array.get(object, i), isApiModel);
            if (i < length - 1) {
                add(',');
            }
        }
        add("]");
    }

    private void bool(
            boolean b) {
        add(b ? "true" : "false");
    }

    private void date(
            Date date) {
        if (format == null) {
            format = new SimpleDateFormat(AlipayConstants.DATE_TIME_FORMAT);
            format.setTimeZone(TimeZone.getTimeZone(AlipayConstants.DATE_TIMEZONE));
        }
        add("\"");
        add(format.format(date));
        add("\"");
    }

    private void string(
            Object obj) {
        add('"');
        CharacterIterator it = new StringCharacterIterator(obj.toString());
        for (char c = it.first(); c != CharacterIterator.DONE; c = it.next()) {
            if (c == '"') {
                add("\\\"");
            } else if (c == '\\') {
                add("\\\\");
            } else if (c == '/') {
                add("\\/");
            } else if (c == '\b') {
                add("\\b");
            } else if (c == '\f') {
                add("\\f");
            } else if (c == '\n') {
                add("\\n");
            } else if (c == '\r') {
                add("\\r");
            } else if (c == '\t') {
                add("\\t");
            } else if (Character.isISOControl(c)) {
                unicode(c);
            } else {
                add(c);
            }
        }
        add('"');
    }

    private void add(
            Object obj) {
        buf.append(obj);
    }

    private void add(
            char c) {
        buf.append(c);
    }

    static char[] hex = "0123456789ABCDEF".toCharArray();

    private void unicode(
            char c) {
        add("\\u");
        int n = c;
        for (int i = 0; i < 4; ++i) {
            int digit = (n & 0xf000) >> 12;
            add(hex[digit]);
            n <<= 4;
        }
    }
}
